html,
body {
    height: 100%;
}

.main-content {
    height: 100%;
    overflow: hidden;
    display: flex;
    background-color: #eee;

    .main-left {
        width: 80px;
        position: relative;

        ul {
            border-right: 1px solid #ccc;

            background-color: #fff;

            li {
                height: 50px;
                line-height: 50px;
                text-align: center;
                border-bottom: 1px solid #ccc;

                &.active {
                    background-color: #eee;

                }
            }
        }
    }

    .main-right {
        flex: 1;
        position: relative;
        margin: 10px;

        ul {
            display: flex;
            flex-wrap: wrap;
            background-color: #fff;

            li {
                width: 25%;
                text-align: center;
            }
        }
    }
}